The invention relates to a device for cooling a vehicle appliance, in particular a battery (for a 42 V electrical system or for hybrid vehicle) or a fuel cell, by means of a coolant. The device has a plurality of identically designed cooling elements through which coolant can flow. These elements can be brought into bearing contact with at least one component which is to be cooled in the vehicle appliance. The elements have a first cooling-element side and an opposite second cooling-element side. The cooling-element sides have connection openings which form inlet and outlet openings for the coolant and are in communication with the interior space of the cooling element.
Devices of this type are known. DE 196 39 115 A1 discloses a plate-like heat exchanger element having one or more flow passages which are laterally separated from one another and run in the interior of the plate, substantially parallel to the plane of the plate, and between respective inlet and outlet points. On each side of the plate-like heat exchanger element, there is a connection opening. Each connection opening forms an inlet or outlet opening for the coolant. These known heat exchanger elements can be used, for example, as a cooling element for high-temperature batteries of electric vehicles. A drawback is that when coolant flows through heat exchanger elements of this type, there is a relatively high loss of operating pressure. Consequently, a relatively complex coolant supply system has to be used to pass the coolant through one or more heat exchanger elements if the required operating pressure is to be built up.
It is an object of the invention to provide a device of this type which experiences relatively low losses of operating pressure when coolant passes through the cooling elements.
To achieve the object, the invention proposes a device, which is distinguished by the first and second cooling-element sides each having at least two connection openings. This allows coolant to pass through a plurality of cooling elements with reduced pressure losses. This advantageous effect increases as the number of connected cooling elements rises. Therefore, a cooling element may have one or two inlet openings for feeding coolant into the interior space of the cooling element and two outlet openings for discharging the coolant from the latter, or for transferring it into a further cooling element. If there is only one inlet opening in the interior of the corresponding cooling element in order to supply this cooling element, the second inlet opening of the same cooling element may be covered in a suitable way. In addition to the reduced losses in operating pressure, cooling elements with two inlet openings ensure that coolant more rapidly passes through the interior space of the element.
Advantageously, an outlet opening of a cooling element is operatively connected to an inlet opening of a further cooling element. Therefore, a single coolant-feed unit can be used to supply coolant to any desired number of cooling elements which are operatively connected to one another, while ensuring a reduced loss of operating pressure.
The connection openings are preferably designed as projections. This enables producing an operative connection between a respective outlet opening of a first cooling element and an associated inlet opening of a second cooling element, which openings are spaced apart so as to form a receiving space for the insertion, for example, of cells of the vehicle appliance which are to be cooled. This makes it possible to create a stable and compact cooling element/cell sandwich structure, with coolant passing through the cooling elements which are operatively connected to one another and in an operationally favorable manner. Alternatively, instead of projections it is also possible to use separate connecting elements (connection tubes) for producing an operative connection between two cooling elements.
Advantageously, an inlet opening of a respective cooling element, located on a first cooling-element side, is arranged coaxially with an outlet opening on a second cooling-element side of the same cooling element. This permits a uniform space to be formed between each two cooling elements which are arranged opposite one another and are operatively connected to one another. Furthermore, a coaxial, diversion-free operative connection of two associated connection openings allows effective reduction of undesirable operating pressure losses in a corresponding transition region between the connection openings.
According to a preferred embodiment, the inlet openings and the outlet openings of a respective cooling element are designed in complementary fashion with respect to one another, as connection stubs or sockets, respectively. In particular, complementary projections of this type make it relatively easy to produce an accurately fitting socket/connection stub operative connection. This prevents leaks of coolant, between two cooling elements which are arranged at a distance from one another, if appropriate with an appropriate seal inserted between them.
Advantageously, each cooling element comprises two geometrically identical cooling element halves which are connected to one another in such a manner as to prevent leaks of coolant. Element halves which are designed in this way are relatively easy to produce and assemble to form a cooling element in terms of the manufacturing technology required.
In a refinement of the invention, each cooling element has a coolant passage which winds from an inlet opening on a first cooling-element side to an outlet opening on a second cooling-element side. Each cooling element has at least two connection openings on the first and second cooling-element sides, and in particular in the case of a coolant passage which winds, for example, in an M shape, this promotes rapid, operationally favorable passage of coolant through the cooling element combined, at the same time, with a reduced operating pressure loss.
The element halves preferably include a plurality of stabilizing studs which are spaced apart from one another. In each case, two stabilizing studs which lie opposite one another are in bearing contact with one another at their end sides. The stabilizing studs, which in particular are stamped inward, are used to provide the cooling elements with a required basic stability or compressive strength, particularly if a plurality of cooling elements are mechanically clamped to produce a compact cooling element/cell sandwich structure with the cells arranged between them. The stabilizing studs increase the overall rigidity of the respective cooling element and ensure a substantially planar design of the cooling element sides which are intended to be in bearing contact with the cells, even after mechanical clamping between the sandwich components (cooling elements, cells) bearing against one another. In this way, operationally favorable passage of coolant through the respective coolant passage and optimized heat transfer from a cell which is to be cooled to the corresponding contact surfaces of the cooling elements which are in bearing contact with the cell are ensured.
According to a preferred embodiment, the connection openings of a respective cooling element are arranged in an edge region on the corresponding cooling-element side. This allows the cells which are to be cooled to be pushed into the spaces between two opposite cooling elements in a single assembly direction. Therefore, it is possible for a plurality of cooling elements to be preassembled to form a dimensionally stable assembly and to be brought into operative connection with a corresponding number of suitably arranged cells by means of a simple pushing movement in a single assembly direction. Then, the entire system can be mechanically clamped together.
The element halves are advantageously designed as surface-structured half shells, so as to form a respective substantially planar contact surface. The surface structuring is used to dimensionally stabilize the half-shells and therefore also the cooling element, while the formation of a substantially planar contact surface is used for effective heat transfer of one cell of the vehicle device which is to be cooled to a cooling element which is in bearing contact.
The cooling elements advantageously each include a through-opening, which is not operatively connected to the coolant passage, for mechanically clamping the cooling elements with vehicle components arranged between them. Mechanical to clamping of successively arranged cooling elements and vehicle components arranged between them (for example cells), so as to form a sandwich structure, which is reliable and also easy in terms of installation, is enabled by through-openings of this type.
According to a further refinement of the invention, the cooling elements are part of a cooling element which, on each end side, has one connection element which includes at least one through-opening and is operatively connected to an associated, intervening element half of a cooling element in such a manner as to prevent leaks of coolant. This type of cooling unit enables designing a particularly dimensionally stable, easy-to-assemble construction, comprising preferably a plurality of cooling elements which are arranged one after the other and are operatively connected to one another. The unit has suitably designed connection elements at its end sides. This ensures a defined supply and removal of coolant to and from the cooling element. It also is intended to impart sufficient stability to the unit for mechanical clamping. For this purpose, the connection elements may, on their outer side, each have component reinforcing fins and may, on their inner side, each have a planar contact surface.
The cooling elements are preferably connected to one another in such a manner as to prevent leaks of coolant. This is done with an operative connection between an inlet opening of a first cooling element and an outlet opening of an opposite, second cooling element. Therefore, two cooling elements which lie opposite one another are operatively connected to one another by two connection openings in a manner as to prevent leaks of coolant. The connection openings may be operatively connected to one another with separate connection elements between them or preferably by means of connection of suitably designed projections on the corresponding cooling elements.
Preferably, inlet and outlet openings of a cooling element, which are arranged coaxially with respect to one another, are directly connected to one another, to form an axial through connection through the cooling element. The associated coolant passage, which extends substantially perpendicular thereto, is connected to the through connection. In this way, the coolant which passes through one cooling element can flow through a respective inlet opening into the coolant passage and/or can directly reach the outlet opening in the same cooling element, which lies coaxially with respect to the inlet opening. Therefore, if appropriate, part of the stream of coolant can flow from a first cooling element coaxially through the inlet and openings thereof into a second, opposite cooling element, without having to pass through the coolant passage. This allows coolant which has not yet been heated or has only been slightly exposed to transferred heat to pass rapidly through all the cooling elements arranged in succession, which is favorable for operation. This advantageously produces relatively low losses of operating pressure, on account of the partial passage through the cooling elements, which is more favorable in terms of flow. This results from a direct connection (bypass connection with respect to the coolant passage) through coaxially arranged inlet and outlet openings of a cooling element, which are directly connected to one another.
The cooling elements which are operatively connected to one another and the connection elements arranged at the end sides are advantageously prefabricated or preassembled as a stable assembly, in order to produce an operative connection, particularly to a plurality of vehicle components which are to be cooled, so as to form a sandwich structure. A prefabricated or preassembled and in particular dimensionally stable assembly of this type can be operatively connected, in a manner which is particularly easy to handle, to a vehicle appliance which is to be cooled, for example in the form of a battery or a fuel cell, since it is merely necessary to produce bearing contact between the corresponding contact surfaces of the cooling elements and the vehicle components. If appropriate, there may be additional mechanical clamping of all the elements and components which are operatively connected to one another.
According to a preferred embodiment, each of the connection elements are operatively connected to element halves of cooling elements, which are connected in parallel with one another, in a manner which prevents coolant leaks. The modular design makes it possible to produce different series and/or parallel arrangements of cooling elements so as to form a dimensionally stable assembly in a relatively simple way. Suitable designing of the connection elements also allows a defined supply or discharge of coolant to be achieved by means of suitable coolant openings in the connection elements. It is advantageously also possible for the design of the assembly to be adapted relatively easily to respective vehicle appliance designs or operating conditions.
The connection elements are preferably of identical design. Therefore, identical connection elements are used both to supply coolant to the assembly and to discharge coolant from the assembly. This reduces costs and simplifies assembly of the device.
The element halves of the cooling elements and the connection elements may be designed as deep-drawn parts and/or as castings. The individual elements of an assembly can therefore be produced in a relatively easy way in terms of production technology.
Further advantageous configurations of the invention will emerge from the description.